Recover expired FTP control sessions

src/test_host.rs

@@ -0,0 +1,50 @@
+//! Native test transport. Guest calls run only inside `spawn_blocking`;
+//! production WASM always uses the host's sockets and network policy.
+
+use std::cell::RefCell;
+use std::io::{Read, Write};
+use std::net::{IpAddr, SocketAddr, TcpStream};
+use std::time::Duration;
+
+pub use memona_plugin_sdk::HostError;
+
+pub struct Tcp(RefCell<TcpStream>);
+
+pub fn connect(name: &str, port: u16, tls: bool) -> Result<Tcp, HostError> {
+  if tls {
+    return Err(HostError::InvalidInput);
+  }
+  let ip: IpAddr = name.parse().map_err(|_| HostError::InvalidInput)?;
+  let timeout = Duration::from_secs(2);
+  let stream = TcpStream::connect_timeout(&SocketAddr::new(ip, port), timeout)
+    .map_err(|_| HostError::Unavailable)?;
+  stream
+    .set_read_timeout(Some(timeout))
+    .map_err(|_| HostError::Unavailable)?;
+  stream
+    .set_write_timeout(Some(timeout))
+    .map_err(|_| HostError::Unavailable)?;
+  Ok(Tcp(RefCell::new(stream)))
+}
+
+impl Tcp {
+  pub fn read(&self, limit: u32) -> Result<Vec<u8>, HostError> {
+    let mut bytes = vec![0; limit as usize];
+    let count = self
+      .0
+      .borrow_mut()
+      .read(&mut bytes)
+      .map_err(|_| HostError::Unavailable)?;
+    bytes.truncate(count);
+    Ok(bytes)
+  }
+
+  pub fn write(&self, bytes: &[u8]) -> Result<u32, HostError> {
+    self
+      .0
+      .borrow_mut()
+      .write(bytes)
+      .map(|count| count as u32)
+      .map_err(|_| HostError::Unavailable)
+  }
+}